City of Mandurah rangers have closed Avalon Beach in Falcon due to a number of shark sightings.
Three bull sharks were spotted about 500 metres off the Yeedong Road boat ramp around 8.40am on Wednesday.
The Surf Life Saving helicopter has also sighted two sharks off Peron in Rockingham.
The two-metre sharks were swimming about 300 metres offshore around 10am.
Point Peron Beach has also been closed.
Beachgoers are reminded to be extra vigilant in the water.
Concerns for missing man last seen in Medina
Man charged after slashing victim's neck with glass in Madora Bay
Rockingham disability accommodation and social housing refurbished thanks to State Government grant
Local fishers asked to have their say on extending crabbing season closure, simplifying bag and boat limit rules
Detectives hunt driver who reversed into Mandurah tobacco store
Mandurah Crab Fest boasts huge range of free, family friendly entertainment
Fuel prices surge in Perth, Mandurah
Teen boys charged over Mandurah burglaries
Tragic update in search for missing man Robert Snyder